Rotary coupling for an article handler

ABSTRACT

A rotary coupling for communicating a pneumatic signal from a stationary pneumatic source to an apparatus. The rotary coupling has a housing and a rotating portion that rotates with respect thereto. The housing has at least two inlets in fluid communication with the pneumatic source. The rotating portion has at least two outlets in fluid communication with the apparatus. Inlet and outlet pairs are aligned radially relative to an axis of rotation of the rotating portion so that they are in fluid communication when the rotating portion is at an angular orientation at which the inlet and outlet pair are coincident. More than one inlet may be paired with an outlet, and vice versa. Channels can be formed to allow the inlet and outlet pairs to be in fluid communication when they are not coincident. Inlets and outlets can also be radially spaced different distances from the axis of rotation such that fluid communication between these inlets and outlets are blocked at all angular orientations of the rotating portion.

This is a division of application Ser. No. 08/559,295 filed Nov. 15,1995 now U.S. Pat. No. 5,810,049.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to a coupling connecting an articlehandler to a source of pneumatic signals, and particularly to a rotarycoupling for selectively blocking and restoring fluid communicationbetween a rotating article handler and the stationary pneumatic signalsource. More particularly, the present invention relates to a rotarycoupling that couples a rotating article handler associated with a heatseal machine to the stationary source of pneumatic signals and thatcontrols the communication of the pneumatic signals therebetween.

Food processing equipment is frequently complex equipment having varioustranslating or rotating moving parts. In addition, food processingequipment can employ pneumatic flow such as vacuum or forced air toeither hold an article against an article handler or to separate thearticle from the article handler. What is needed is a rotary couplingthat can couple a stationary source of pneumatic signals to a rotatingportion of an article handler to allow fluid communication therebetween.Equipment manufacturers and operators of food processing equipment wouldappreciate food processing equipment having such a rotary coupling thatis capable of communicating pneumatic flow through multiple channels andconduits, that is capable of restricting the communication of thepneumatic flow so that the pneumatic flow is available only duringselected portions of the rotation cycle of the article handler, and thatis capable of communicating both vacuum and forced air signals.

According to the present invention, a rotary coupling is provided. Therotary coupling controls the communication of pneumatic signals from astationary pneumatic signal source to an apparatus. The rotary couplingcomprises a housing having an inlet in fluid communication with thepneumatic signal source and a rotating portion received in the housingfor rotation with respect thereto. The rotating portion has an outlet influid communication with the apparatus. The inlet and the outlet areradially aligned relative to an axis of rotation of the rotating portionso that the inlet and the outlet are in fluid communication when therotating portion is at an angular orientation at which the inlet and theoutlet are coincident.

In preferred embodiments, the rotary coupling connects a rotatingarticle handler associated, for example, with a heat seal machine to thesource of pneumatic signals. The pneumatic signal source canillustratively include a vacuum source or a source of pressurized air. Arotating shaft, including a conduit in fluid communication with both thearticle handler and the rotary coupling, rotates the article handler. Asthe shaft rotates, the rotating article handler alternately liftsarticles using suction force when the rotary coupling connects thearticle handler to the vacuum source and releases the articles when therotary coupling removes the suction by disconnecting the article handlerfrom the vacuum source and connecting the article handle to the sourceof pressurized air.

The rotary coupling in accordance with the present invention controlsand "programs" the communication of pneumatic signals from the pneumaticsignal source to the article handler. The rotary coupling establishesthe sequencing of the pneumatic signals as well as the timing andduration of the signals. As the shaft rotates, the coupling selectivelyblocks and restores fluid communication between the article handler andthe pneumatic signal source to communicate the pre-programmed pneumaticsignals at each portion of the rotation cycle of the article handler. Inaddition, the coupling can be readily and easily adjusted to retard oradvance the timing of the pneumatic signals. Also, the sequencing ofsignals can be changed entirely simply by changing a stationary padinside of the coupling, completely "reprogramming" the sequence ofpneumatic signals.

The rotary coupling includes a housing defining a cavity. The housingincludes an end cap and the stationary pad which is supported by the endcap inside the cavity in a radially fixed orientation relative to theend cap for slight axial movement relative to the end cap. Thestationary pad has an opening extending through the pad that is in fluidcommunication with an opening in the end cap. The opening in the end capis in fluid communication with the source of pneumatic signals.

The rotary coupling also includes the shaft having a first end coupledto the rotating article handler of the equipment and a second end havingan end portion rotatably received by the housing. The end portionincludes a rotating pad supported in the cavity for slight axialmovement relative to the shaft but in a radially fixed orientationrelative to the shaft. The rotating pad thus rotates relative to thestationary pad.

The stationary pad has a first sealing face that is preferably veryfinely machined, ground flat, and then lapped to near perfect flatness.Likewise, the rotating pad has a second sealing face that is preferablyvery finely machined, ground flat, and then lapped to near perfectflatness. The shaft is received in the housing so that the first sealingface sealingly engages the second sealing face.

Sealing engagement of the first and second sealing faces is achieved inpart by providing the first and second sealing faces with near perfectflatness as described above. In addition, the stationary and rotatingpads are mounted so that the pads axially "float" between the end capand the end portion of the main shaft. This float is achieved byproviding the axially slidable connections between the stationary padand the end cap and between the rotating pad and the end portion of themain shaft and by yieldably biasing the stationary pad away from the endcap and yieldably biasing the rotating pad away from the end portion ofthe main shaft so that the stationary and rotating pads are biasedtoward one another.

The stationary pad is yieldably biased away from the end cap by o-ringsmade from a resilient material positioned to lie between the stationarypad and the end cap. Likewise, the rotating pad is yieldably biased awayfrom the end portion of the main shaft by o-rings made from a resilientmaterial positioned to lie between the rotating pad and the end portionof the main shaft. These o-rings allow the stationary pad to movesightly in an axial direction relative to the end cap and the rotatingpad to move slightly in the axial direction relative to the main shaft.The o-rings also allow the pads to adjust so that pads are notnecessarily precisely parallel to the end cap or the end portion of theshaft, thus ensuring the sealing engagement between the sealing faceswhen opposing faces of the end portion and the end cap are not preciselyparallel.

The rotating pad is formed to include an opening that extends throughthe rotating pad. The opening in the rotating pad is in fluidcommunication with the article handler through the conduit of the shaft.

The opening in the rotating pad and the opening in the stationary padare radially aligned so that the openings coincide during apredetermined portion of each rotation cycle of the shaft and therotating pad relative to the housing and the stationary pad. When theopenings in the stationary and rotating pads are coincident, theopenings are in fluid communication so that the article handler is influid communication with the pneumatic signal source. When the openingsin the stationary and rotating pads are not coincident, the sealingengagement between the first and second sealing faces blocks the fluidcommunication between the openings in the rotating and stationary pads,blocking the fluid communication between the pneumatic signal source andthe article handler. Thus, the positioning of the openings in thestationary and rotating pads operates to program the rotary coupling tocommunicate the pneumatic signal from the pneumatic signal source to thearticle handler when the article handler is at a predetermined angularorientation.

The rotating and stationary pads can additionally cooperate to define anarcuate channel in fluid communication with the openings in the rotatingand stationary pads at selected portions of the rotation cycle. Thechannel operates to maintain the fluid communication between theopenings in the rotating and stationary pads during portions of therotation cycle at which the openings are not coincident. The channel, ineffect, lengthens the portion of the rotation cycle of the shaft duringwhich the openings in the rotating and stationary pads are in fluidcommunication, thereby lengthening the duration of the communication ofthe pneumatic signal from the pneumatic signal source to the articlehandler.

Lengthening the channel lengthens the portion of the rotation cycleduring which the openings are in fluid communication. In addition, thechannels can be formed so that the openings are not centered within thechannel. Instead, the channel can be formed, for example, so that thefluid communication starts earlier in the rotation cycle and endsearlier in the rotation cycle than would occur if the opening wascentered in the channel. Likewise, the channel can be formed so that thefluid communication is restored later and is blocked later in the cyclethan would occur if the opening were centered in the channel. It can beseen, then, that the channel can be used to alter both the orientationof the shaft at which the openings in the rotating and stationary padsare in fluid communication and the extent of the rotation cycle duringwhich the openings in the rotating and stationary pads are in fluidcommunication, thus varying the timing and duration of the communicationof pneumatic signals between the pneumatic signal source and the articlehandler.

It is preferred that the channel is formed in the stationary pad,however channels can be formed in both the stationary and rotating padsor in only the rotating pad without altering the scope of the inventionas presently perceived. It can be seen that if the channel is formed onthe stationary pad, for example, the sequencing and duration of thecommunication of pneumatic signals between the article handler and thepneumatic signal source can be easily changed by replacing thestationary pad with a different stationary pad having a channel with adifferent configuration than the channel on the replaced stationary pad.

Additional objects, features, and advantages of the invention willbecome apparent to those skilled in the art upon consideration of thefollowing detailed description of a preferred embodiment exemplifyingthe best mode of carrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the accompanying figuresin which:

FIG. 1 is a top plan view of an article handler showing a chain drivinga sprocket (not shown) attached to a shaft including a first end coupledto an article handler having suction cup lifting arms positioned above aconveyor carrying packages of processed food (not shown) and a secondend received by a housing of a rotary coupling in accordance with thepresent invention;

FIG. 2 is a sectional view taken along line 2--2 of FIG. 1 showing therotary coupling including the housing, the shaft received in the housingand extending outwardly therefrom, the shaft including a widened endportion received in the housing and having openings in fluidcommunication with the article handler and a rotating pad radially fixedto the end portion, the housing including an end cap having openings influid communication with the source of pneumatic signals and astationary pad radially fixed to the end cap, the rotating andstationary pads having openings in fluid communication with therespective openings of the end portion and the end cap, the rotating padsealingly engaging the stationary pad;

FIG. 3 is an exploded perspective view of the rotary coupling of FIG. 1showing the housing, a turnbuckle connected to the housing to fix thehousing circumferentially relative to a wall (not shown), the shaftextending through the housing, the widened end portion of the shaftbeing formed to include a plurality of openings, the rotating pad beingrotatably fixed relative to the end portion and having openingsextending therethrough, the openings of the rotating pad aligning withopenings in the end portion, the stationary pad of the housing sealinglyengaging the rotating pad and having openings therethrough, and the endcap of the housing having a conduit network formed therein, the conduitnetwork including openings aligning with the openings in the stationarypad;

FIG. 4 is an elevation view of a first sealing face formed on thestationary pad showing channels formed in the face and openingsextending through the stationary pad, the openings being in fluidcommunication with the channels and being configured to align withopenings (not shown) formed on the end cap (not shown) so that thechannels are in fluid communication with the openings in the end cap;and

FIG. 5 is an elevation view of a second sealing face formed on therotating pad that sealingly engages the first sealing face (not shown)showing openings extending through the pad and configured to align withopenings (not shown) formed in the shaft (not shown) so that theopenings in the rotating pad are in fluid communication with theopenings in the shaft.

DETAILED DESCRIPTION OF THE DRAWINGS

A rotary coupling 10 in accordance with the present invention andillustratively shown in FIG. 1 is coupled to a rotatable article handler12 illustratively associated with a heat seal machine (not shown).Packages (not shown) are carried by a conveyor 14 that carries thepackages along a path adjacent to article handler 12. Article handler 12includes arms 16, 18 having cups 20 that pick-up articles (not shown)from a supply stack of articles (not shown) and places the articles onthe packages.

Article handler 12 includes a main shaft 22 rotated by a chain-drivensprocket 23 as shown in FIG. 1. Main shaft 22 has a first portion 24connected to article handler 12 and extending through a wall 26 to anend portion 28 received by rotary coupling 10 as shown in FIGS. 1 and 2.First portion 24 of main shaft 22 is keyed to a bar 30 carrying handlershafts 32. Handler shafts 32 are rotatably coupled to bar 30 and extendtherethrough for rotation relative to bar 30. Blocks 34 carrying arms16, 18 are keyed to handler shafts 32 for rotation with handler shafts32 relative to bar 30. Each handler shaft 32 is additionally keyed torotate with a guide arm 36 carrying a rotatable roller 38.

An annular plate 40 is fixed to wall 26 as shown in FIG. 1. Plate 40 isformed to include a channel 42 defining a roller guide path 44. As mainshaft 22 rotates about an axis of rotation 46, bar 30 rotates causinghandler shafts 32 to orbit about axis 46. As handler shafts 32 orbitabout axis 46, rollers 38 follow roller guide path 44. Roller guide path44 guides rollers 38 from side to side relative to handler shafts 32,thereby causing handler shafts 32 and blocks 34 carrying arms 16, 18 torotate from side to side mimicking the motion of guide arms 36 androllers 38 as rollers 38 trace along roller guide path 44. Thus, as mainshaft 22 rotates, handler shafts 32 and arms 16, 18 orbit main shaft 22and arms 16, 18 move from side to side relative to handler shafts 32along a path parallel to path 44 defined by channel 42 of plate 40.

Main shaft 22 is formed to include axially-extending conduits 47including conduits 48, 50 as shown in FIG. 2. Conduits 48, 50 are influid communication with nipples 52, 54 fixed to main shaft 22 shown inFIG. 1. Nipple 52 is in fluid communication through a tube 56 with anipple 58 fixed to bar 30 and nipple 54 is in fluid communicationthrough a tube 60 with a nipple 62 fixed to bar 30. Further, nipple 58is in fluid communication with arms 16 through tubes 66, through anipple 64 fixed to bar 30, and through a cavity (not shown) formed inbar 30. Also, nipple 62 is in fluid communication with arms 18 throughtubes 70, through a nipple 68 fixed to bar 30, and through a secondcavity (not shown) formed in bar 30, so that conduit 48 of main shaft 22is in fluid communication with arms 16 and conduit 50 of main shaft 22is in fluid communication with arms 18.

During each rotational cycle of article handler 12, arms 16, 18 move asthe result of the rotation of main shaft 22 and the movement of rollers38 to complete article handling movements that are coordinated with thecommunication of pneumatic signals between a pneumatic signal source 39and the article handler 12. The handling movements and pneumatic signalscoordinated therewith as described below for arms 16 are similar tothose relating to arms 18.

Cups 20 of arms 16 move to engage the top article (not shown) in a stack(not shown) of articles as conduit 48 of main shaft 22 rotates intofluid communication with a vacuum source (not shown) of pneumatic signalsource 39. Vacuum is communicated from the vacuum source through conduit48, nipple 52, tube 56, nipple 58, nipple 64, and tubes 66 to arms 16and cups 20 so that the vacuum holds the top article against cups 20.Continued rotation of main shaft 22 moves arms 16 and the top articlecarried thereon from the supply stack to a position holding the articleover a package.

As the article moves over the package, conduit 48 rotates to a positionblocking the fluid communication between arms 16 and the vacuum source.Conduit 48 then rotates into fluid communication with a pressurized airsource (not shown) of pneumatic signal source 39. The pressurized air iscommunicated to cups 20 so that the article is blown free from cups 20and is placed onto the package upon which heat sealing operations can beperformed. Rotary coupling 10 operates to couple rotating articlehandler 12 through rotating main shaft 22 to the source of pneumaticsignals 39, for example to the vacuum source and to the source ofpressurized air, and to "program" the delivery of the pneumatic signalsto article handler 12.

Rotary coupling 10 includes a housing 80 that is radially fixed relativeto wall 26 by a turnbuckle 82 as shown in FIG. 1 and that is axiallymovable relative to main shaft 22. Housing 80 includes a cylindricalside wall 84 and an end cap 86 cooperating with side wall 84 to define acavity 88 as shown in FIGS. 2 and 3.

Cylindrical side wall 84 is formed to include a radially inwardlyextending step 90 having an inwardly-facing step surface 92 opposing endcap 86. End portion 28 of main shaft 22 is received in cavity 88 andmain shaft 22 extends outwardly therefrom through an opening 94 definedby step 90. Bearings 74 are interposed between first portion 24 of mainshaft 22 and housing 80 and between end portion 28 and housing 80 asshown in FIG. 2. o-rings 76 are likewise interposed between firstportion 24 of main shaft 22 and housing 80 and between end portion 28and housing 80 as shown in FIGS. 2 and 3.

First portion 24 of main shaft 22 has a first diameter 96 and endportion 28 has a second diameter 98 that is greater than first diameter96 as shown in FIGS. 2 and 3. A loading surface 100 connects end portion28 to first portion 24 and cooperates with cylindrical side wall 84,step surface 92, and first portion 24 of main shaft 22 to define anannular loading chamber 110 that is a portion of cavity 88 as shown inFIG. 2.

Rotary coupling 10 further includes a stationary pad 112 and a rotatingpad 114 received by cavity 88 as shown in FIGS. 2 and 3. Stationary pad112 engages end cap 86 and is formed to include stationary pad openings115 including openings 116, 118, 120, 122, 124, 126, 128, 130 extendingtherethrough as shown in FIGS. 2 and 4. In preferred embodiments,stationary pad 112 is also formed to include channel system 132including channels 134, 136, 138, 140, 142, 144, 146, 148 adjacent toand in fluid communication with openings 116, 118, 120, 122, 124, 126,128, 130 respectively as shown in FIG. 4. In preferred embodiments, thechannels of channel system 132 are circumferentially extending channelsformed in one surface of stationary pad 112.

Rotating pad 114 is sandwiched between end portion 28 of main shaft 22and stationary pad 112 and is formed to include rotating pad openings149 including openings 150, 152, 154, 156, 158, 160, 162, 164 extendingtherethrough as shown in FIGS. 3 and 5. Openings 150, 152, 154, 156,158, 160, 162, 164 are in fluid communication with axially extendingconduits 47 of main shaft 22 including openings 48, 50, 210, 212, 214,216, 218, 220, respectively, as shown in FIGS. 2 and 3. As describedabove, in preferred embodiments stationary pad 112 is formed to includechannel system 132. However, rotating pad 114 can be formed to includechannel system 132, or both rotating pad 114 and stationary pad 112 canbe formed to include portions of channel system 132 without exceedingthe scope of the invention as presently perceived.

In presently preferred embodiments, end cap 86 is formed to include acylindrical side 166 and an inner surface 168 inside of cavity 88 asshown in FIG. 3. End cap 86 is further formed to include a conduitnetwork 170 having radially extending conduits 172, 174, 176, 178, 180,182, 184 that extend radially inwardly relative to axis 46 fromcylindrical side 166 of end cap 86 as shown best in FIG. 3. Conduitnetwork 170 further includes axially extending conduits 186, includingconduits 188, 190, 192, 194, 196, 198, 200, 202 that extend axiallyoutwardly from surface 168.

Illustratively, axially extending conduits 188, 190 are in fluidcommunication with radially extending conduit 172 and axially extendingconduits 192, 194, 196, 198, 200, 202 are in fluid communication withradially extending conduits 174, 176, 178, 180, 182, 184 respectively asshown in FIG. 3. Radially extending conduits 172, 174, 176 are in fluidcommunication with a source of pressurized air (not shown) of pneumaticsignal source 39 and radially extending conduits 178, 180, 182, 184 arein fluid communication with a source of vacuum (not shown) of pneumaticsignal source 39 so that axially extending conduits 188, 190, 192, 194are in fluid communication with a source of pressurized air and axiallyextending conduits 196, 198, 200, 202 are in fluid communication with avacuum source. Although the presently preferred and illustrativeembodiment includes the above-described conduit system 168, any systemof conduits having a configuration bringing at least one conduit onsurface 168 into fluid communication with a source of pneumatic signals39 is within the scope of the invention as presently perceived.

Stationary pad 112 is rotatably fixed to end cap 86 and is axiallymoveable with respect thereto. Pins 222 are threadably received by endcap 86 and are slidably received by recesses 224 formed in stationarypad 112 as shown in FIGS. 2 and 3 to prevent rotation of stationary pad112 relative to end cap 86. End cap 86 is further formed to includegrooves 226 for receiving o-rings 228 adjacent to axially extendingconduits 186 as well as grooves 230 for receiving o-rings 232. o-rings228 sealingly engage stationary pad 112 and end cap 86 adjacent toconduits 186 of end cap 86 and stationary pad openings 115 as shown, forexample, in FIG. 2. o-rings 232 are "dummy" o-rings provided to cushionstationary pad 112 against end cap 86 on the portion of stationary pad112 away from openings 115 and conduits 186. o-rings 228 and o-rings 232also cooperate to yieldably bias stationary pad 112 away from end cap86.

Likewise, rotating pad 114 is rotatably fixed to end portion 28 of mainshaft 22 and is axially moveable with respect thereto. Pins 236 arethreadably received by end portion 28 and are slidably received byrecesses 238 formed in rotating pad 114 as shown in FIGS. 2 and 3 toprevent rotation of rotating pad 114 relative to end portion 28. Endportion 28 is further formed to include grooves 240 for receivingo-rings 242 adjacent to axially extending conduits 47 of end portion 28.o-rings 242 sealingly engage rotating pad 114 and end portion 28adjacent to conduits 47 of end portion 28 and rotating pad openings 149as shown, for example, in FIG. 2. o-rings 242 additionally operate toyieldably bias rotating pad 114 away from end portion 28.

Stationary pad 112 includes a first sealing face 250 and rotating padincludes a second sealing face 252 engaging first sealing face 250 asshown in FIGS. 2-5. The first and second sealing faces 250, 252 are bothplanar and smooth to permit the sealing engagement of the first andsecond sealing faces 250, 252. Preparation of the sealing faces 250, 252can include, for example, finely machining the faces 250, 252, grindingthe faces 250, 252 flat, and then lapping the faces 250, 252. Byachieving planar and smooth faces 250, 252, a seal can be formedtherebetween when faces 250, 252 are in engagement.

In addition, stationary pad 112 and rotating pad 114 "float" in cavity88 between o-rings 228, 232 and o-rings 242 as shown best in FIG. 2.This float is achieved by supporting pads 112, 114 between resiliento-rings 228, 232, 242 thus allowing pads 112, 114 to make slight axialadjustments relative to end cap 86 and end portion 28 of main shaft 22to compensate for slight tolerance inconsistencies such as, for example,misalignments of main shaft 22 relative to housing 80, and to ensurethat first and second sealing faces 250, 252 mate against one anotherand are sealingly engaged.

Housing 80 can further be provided with a loading port 254 in fluidcommunication with loading chamber 110 of cavity 88 and a return port256 in fluid communication with a portion of cavity 88 outside ofloading chamber 110 as shown in FIG. 2. Loading port 254 is additionallyin fluid communication with a source of pressurized fluid 258 and returnport 256 is additionally in fluid communication with a reservoir 260holding fluid at atmospheric pressure. As a result, the pressurizedfluid in loading chamber 110 yieldably biases loading surface 100 awayfrom step surface 92 to bias the first and second sealing faces 250, 252together.

Main shaft 22 is axially fixed relative to wall 26 but housing 80 isfree to move axially relative to main shaft 22 so that pressurizing thefluid in loading chamber 110 yieldably biases step surface 92 away fromloading surface 100 causing housing 80 to move toward article handler12, thus yieldably biasing end cap 86 and stationary pad 112 againstrotating pad 114 and end portion 28 of main shaft 22. Biasing firstsealing face 250 of stationary pad 112 against second sealing face 252of rotating pad 114 enhances the sealing engagement therebetween byforcing additional adjustment of the pads 112, 114 relative to o-rings228, 232, 242, end cap 86, and end portion 28 and by pressing thealready planar sealing faces 112, 114 into a further conformingengagement.

The fluid of the source of pressurized fluid 258, loading chamber 110,and reservoir 260 can be essentially any generally inert fluid such asair or oil. Preferably, the fluid is oil or another lubricating fluid sothat as some of the fluid leaks from loading chamber 110 to cavity 88outside of loading chamber 110 it also lubricates end portion 28 andhousing 80 as end portion 28 rotates relative to housing 80. In thepreferred embodiment, the pressurized fluid is oil and the oil ispressurized by applying pressurized air to the oil to control thepressure of fluid 258.

Stationary pad 112 and rotating pad 114 cooperate to control theduration and frequency of pneumatic signals communicated from thepneumatic signal source 39 and article handler 12. In the presentlypreferred embodiment, stationary pad 112 includes stationary padopenings 115 and channel system 132 as shown best in FIG. 4. Channelsystem 132 and openings 115 cooperate with rotating pad openings 149 toprogram the timing and duration of the communication of pneumaticsignals from pneumatic signal source 39 to article handler 12 asrotating pad 114 and end portion 28 of main shaft 22 rotate relative tostationary pad 112.

Channel system 132 includes four pairs of circumferentially extendingelongated channels including channels 134, 142; 136, 144; 138, 146; and140, 148. Both channels in each of the above-noted pairs of channels areradially spaced apart from axis of rotation 46 a generally equaldistance. Each pair of channels includes a channel in fluidcommunication with a vacuum source including channels 142, 144, 146,148, and a channel in fluid communication with a source of pressurizedair including channels 134, 136, 138, 140.

Rotating pad 114 includes rotating pad openings 149 and second sealingface 252 that sealing engages first sealing face 250 as shown in FIG. 5.Rotating pad openings 149 are in fluid communication with conduits 47 ofmain shaft 22.

Illustratively, the following conditions arise when main shaft 22 androtating pad 114 are in an initial orientation relative to stationarypad 112 and end cap 86 as shown in FIG. 2. Opening 152 in rotating pad114 is coincident with channel 134 and opening 116 of stationary pad 112to restore fluid communication between opening 152 and opening 116, thusrestoring fluid communication between pneumatic signal source 39 andconduit 50 of main shaft 22. For another example, the sealing engagementbetween first and second sealing faces 250, 252 blocks fluidcommunication between opening 118 and channel 136 of stationary pad 112and conduits 47 of main shaft 22. Also, the sealing engagement betweenthe first and second faces 250, 252 sealingly encloses channels 146, 148where second face 252 engages portions of first face 250 surroundingchannels 146, 148. Finally, the sealing engagement between the first andsecond sealing faces 250, 252 blocks fluid communication between opening150 of rotating pad 114 and channel system 132 and openings 115 ofstationary pad 112, thereby blocking the fluid communication betweenconduit 48 and pneumatic signal source 39.

Each rotating pad opening 149 is radially aligned with a pair ofchannels of channel system 132 so that during rotation of rotating pad114 each rotating pad opening 149 is alternately in fluid communicationwith each channel of the pair of channels. For example, rotating padopening 150 is in a sealed position when stationary pad 112 is orientedas shown in FIGS. 2 and 4 and rotating pad 114 is in the initialorientation shown in FIGS. 2 and 5 so that conduit 48 is not in fluidcommunication with pneumatic signal source 39. End portion 28 androtating pad 114 rotate so that opening 150 and conduit 48 progress fromthe sealed position to a position aligned with channel 142 and in fluidcommunication with the vacuum source through channel 142 and opening124. Continued rotation moves opening 150 past channel 142 and betweenchannel 142 and channel 134, the sealing engagement between sealingfaces 250, 252 blocking fluid communication between opening 150 andchannels 142, 134. Still further rotation brings opening 150 into fluidcommunication with the pressurized air source through channel 134 andopening 116, followed by rotation to yet another sealed position betweenchannel 134 and channel 142 eventually moving opening 150 back to theinitial orientation shown in FIGS. 2 and 5. This cycle is repeated foreach revolution of rotating pad 114 relative to stationary pad 112.

Similar cycles are completed for the other seven rotating pad openings149. For example, opening 152 and conduit 50 are in fluid communicationwith the pressurized air source through channel 134 and opening 116 whenrotating pad 114 is in the initial position shown in FIGS. 2 and 5. Asrotating pad 114 rotates, opening 152 moves to a sealed position havingthe edge of opening 152 engaging sealing face 250 to block the fluidcommunication between openings 152 and channel system 132. Opening 152is then moved to fluid communication with the vacuum source throughchannel 142 and opening 124, to another sealed position having the edgeof opening 152 engaging sealing face 250, and back to fluidcommunication with channel 134 as rotating pad 114 completes a fullrevolution or cycle. For yet another example, opening 154 is in fluidcommunication with the vacuum source through channel 146 and opening 128in the initial position. As rotating pad 114 rotates through a completerevolution or cycle, opening 154 moves to a sealed position, to fluidcommunication with the pressurized air source through channel 138 andopening 120, to another sealed position, and to fluid communication withchannel 146.

In the illustrative and preferred embodiment of rotary coupling 10,pairs of rotating pad openings 149 are radially aligned with each pairof channels, the openings of each pair of openings being spaced-apart by180 degrees (180°). For example, openings 150, 152 are radially alignedwith channels 142, 134 as shown in FIGS. 2, 4, and 5; openings 154, 164are radially aligned with channels 146, 138; openings 158, 160 areradially aligned with channels 144, 136; and openings 162, 156 areradially aligned with channels 148, 140. This allows pneumatic signalsfrom each pair of channels to alternately communicate with two sets ofarms 16, 18 through two openings 149 of rotating pad 114 and twoconduits 47 of main shaft 22.

As described above, stationary pad 112 contains the "programming" thatcontrols the duration and frequency of the communication of pneumaticsignals between pneumatic signal source 39 and article handler 12. Ascan be seen, the programming is encoded through the configuration ofchannel system 132 and stationary pad openings 115 relative to rotatingpad openings 149. It should be clear, however, that the program can beencoded on rotating pad 114 by forming channel system 132 on rotatingpad 114 or on both pads 112, 114 by forming portions of channel system132 on each pad 112, 114.

Additionally, the programming can be changed in the preferred embodimentby replacing stationary pad 112 with a new stationary pad having adifferent program encoded. For example, by plugging stationary padopenings 116, 118, 120, 122, the fluid communication of rotating padopenings 149 with the source of pressurized air can be eliminated. Foranother example, by extending the length of channels 142, 144, 146, 148,the duration of the fluid communication between rotating pad openings149 and the vacuum source can be extended. For yet another example, byshifting the circumferential location of channels 134, 136, 138, 140,the timing of the start and finish of the fluid communication ofrotating pad openings 149 with the pressurized air source can beadjusted relative to the orientation of main shaft 22. Thus, the programcontrolling the fluid communication between article handler 12 andpneumatic signal source 39 can be changed by replacing stationary pad112 with a new stationary pad having any changes of the type describedabove or similar thereto, or a combination of changes made on any or allof the stationary pad openings or the channels of the new stationarypad.

Also as described above, stationary pad 112 and end cap 86 arecircumferentially fixed relative to wall 26 and article handler 12 byturnbuckle 82 as shown in FIG. 3. However, turnbuckle 82 can belengthened or shortened to adjust the circumferential orientation ofhousing 80, end cap 86, and stationary pad 112 relative to articlehandler 12. This circumferential adjustment of housing 80, end cap 86,and stationary pad 112 will operate to advance or retard the timing ofthe communication of the pneumatic signals to article handler 12 similarto the effect of providing a new stationary pad in which the orientationof the channel system is adjusted. This adjustment may be useful for"fine tuning" the timing of the supply of pneumatic signals to articlehandler 12 during operation of article handler 12.

During operation of article handler 12, the movement of arms 16, 18 isdictated by the shape of channel 42 of annular plate 40 as describedabove with respect to FIG. 1. As main shaft 22 rotates, arm shafts 32carrying arms 16, 18 orbit main shaft 22 and move in accordance with themovement of rollers 38 following channel 42. The path followed by arms16, 18 is similar to the path followed by rollers 38.

As main shaft 22 rotates, end portion 28 and rotating pad 114 rotaterelative to end cap 86 and stationary pad 112 so that conduits 47 formedin main shaft 22 selectively communicate pneumatic signals betweenpneumatic signal source 39 and article handler 12 as described above.The program encoded as the result of the configuration of channel system132, stationary pad openings 115, and rotating pad openings 149cooperates with article handler 12 so that rotating pad openings 149 arein fluid communication with the vacuum source (not shown) of pneumaticsignal source 39 through channel system 132 and stationary pad openings115 when cups 20 of arms 16, 18 are to hold the articles (not shown)being handled.

As main shaft 22 continues to rotate, arms 16, 18 move the articles (notshown) toward a desired placement position. When the article reaches thedesired placement position, the encoded program has the rotating padopenings 115 in fluid communication with the pressurized air source (notshown) of pneumatic signal source 39 through channel system 132 andstationary pad openings 115 so that the article is released and properlyplaced. Adjusting turnbuckle 82 to adjust the circumferentialorientation of housing 80, end cap 86, and stationary pad 112 operatesto adjust the position of arms 16, 18 at which the fluid communicationbetween article handler 12 and pneumatic signal source 39 is restoredand blocked.

In the presently preferred and illustrative embodiment, eight conduits47 are formed in main shaft 22 allowing for the communication ofpneumatic signals to eight individually programmed sets of arms 16, 18.In the preferred embodiment, pairs of rotating pad openings 149 arestaggered to match the pattern of channels in stationary pad 112 so thattwo sets of arms 16, 18 receive the same pneumatic signal generallysimultaneously.

For example, rotating pad openings 150, 156 are generally simultaneouslybrought into fluid communication with the vacuum source through channels142, 148, respectively, when rotating pad 114 is at a selected angularorientation. Afterward, rotating pad openings 150, 156 are brought intofluid communication with the source of pressurized air through channels134, 140, respectively, at another selected angular orientation.Likewise, each opening of the pairs of rotating pad openings 160, 164;152, 162; and 154, 158 are generally simultaneously brought into fluidcommunication with pairs of channels 144, 146 followed by 136, 138; 142,148 followed by 150, 156; and 152, 162, followed by 154, 158,respectively, so that pairs of sets of arms 16, 18 receive the samepneumatic signal generally simultaneously.

In addition, in the presently preferred rotating pad 114, staggeredpairs of rotating pad openings 149 are spaced apart from other staggeredpairs of rotating pad openings 149 by 180 degrees (180°), thusmaximizing the spacing between the pairs of openings. For example,openings 150, 156, are 180 degrees (180°) spaced-apart from openings152, 162. Likewise, openings 154, 158 are 180 degrees (180°)spaced-apart from openings 164, 160. This spacing maximizes theflexibility afforded to the configuration of channel system 132 whilealso allowing arms 16, 18 associated with each pair of openings 149 tobe 180 degrees (180°) out of phase during their movement.

Rotary coupling 10 in accordance with the present invention is usefulfor article handling applications in which it is desirable to passpneumatic flow through a rotary joint from a stationary side to arotating side of the rotary joint. Particularly, rotary coupling 10 isuseful for article handling applications in which the timing of thepneumatic flow needs to be controlled. As described above, rotarycoupling 10 is capable of communicating pneumatic flow through multiplechannels and conduits, of restricting the communication of the pneumaticflow so that the pneumatic flow is available only at selected portionsof the cycle, and of "2-way" communication for communicating both vacuumand forced air signals. Additionally, rotary coupling 10 allows for easyadjustment of the flow timing through adjustment of the rotationalorientation of housing 80, while being able to self-adjust axially formanufacturing tolerance variability or other variations.

Although the invention has been described in detail with reference tothe preferred embodiment, additional variations and modifications existwithin the scope and spirit of the invention as described and defined inthe following claims.

We claim:
 1. A rotary coupling for communicating pneumatic signals froma stationary source of pneumatic signals to an apparatus, the rotarycoupling comprisinga housing including a cylindrical side wall, an endcap, and a stationary pad coupled to the end cap for axial movement withrespect thereto, the stationary pad having a first sealing face, and ashaft having an end portion rotatably received by the housing, the shaftincluding a rotating pad coupled to the end portion for axial movementwith respect thereto, the rotating pad having a second sealing faceengaging the first sealing face, the stationary pad being yieldablybiased away from the end cap and toward the rotating pad and therotating pad being yieldably biased away from the end portion and towardthe stationary pad so that the stationary pad and the rotating pad floatrelative to the end cap and the end portion of the shaft.
 2. The rotarycoupling of claim 1, wherein the stationary pad is yieldably biased awayfrom the end cap by an o-ring made from a resilient material, the o-ringbeing positioned to lie between the stationary pad and the end cap. 3.The rotary coupling of claim 2, wherein the stationary pad includes anedge defining an opening, the end cap includes an edge defining anopening in fluid communication with the source of pneumatic signals, andthe o-ring sealingly engages the edge of the stationary pad and the edgeof the end cap to form a seal therebetween.
 4. The rotary coupling ofclaim 2, wherein the rotating pad is yieldably biased away from the endportion of the main shaft by an o-ring made from a resilient material,the o-ring being positioned to lie between the rotating pad and the endcap.
 5. The rotary coupling of claim 1, wherein the rotating pad isyieldably biased away from the end portion of the main shaft by ano-ring made from a resilient material, the o-ring being positioned tolie between the rotating pad and the end cap.
 6. The rotary coupling ofclaim 4, wherein the rotating pad includes an edge defining an opening,the end portion of the shaft includes an edge defining an opening influid communication with the apparatus, and the o-ring sealingly engagesthe edge of the rotating pad and the edge of the end portion to form aseal therebetween.